Electrical conductivity and vibrational studies induced phase transition in [N(C3H7)4]2ZnBr4 compound

Bis-Tetrapropylammonium tetrabromozincate was synthesized and characterized by X-ray powder diffraction, as well as vibrational and impedance spectroscopy. Rietveld’s refinement of X-ray diffractogram confirmed the crystallization of the compound through the monoclinic system (space group [Formula: see text]. A temperature study of Raman scattering revealed two phase transitions at approximately [Formula: see text] = 340 K and [Formula: see text] = 393 K. The wavenumber and the line width’s evolution as a function of temperature showed some peculiarities associated with these transitions, which suggests that they are governed by the reorientation of the organic part [N(C3[Formula: see text]][Formula: see text]. The complex impedance plotted as a double semicircular arc in the studied temperature range and the centers of these semicircles lie below the real axis, which indicates that the material is an on-Debye type. These semicircular arcs are related to the bulk and the grain boundary effects. Furthermore, the alternating current conductivity of [N(C3[Formula: see text]]2ZnBr4 obeyed Jonscher’s law: [Formula: see text] = [Formula: see text] and the conduction could be attributed to the correlated barrier hopping (CBH) model in both region(I) and (II) and the Non-overlapping Small Polaron Tunneling (NSPT) in region (III).

X-Ray, DSC, TGA-dTGA, and Vibrational Studies of the Propylenediammonium Hexafluorosilicate NH3(CH2)3NH3SiF6

X-ray characterization, thermal behavior, and vibrational studies have been performed on NH3(CH2)3NH3SiF6, which crystallized in the P21/c (Z = 4) monoclinic system. The V/Z ratio variation (unit cell volume/ motifs number per cell) versus the CH2 groups’ number is discussed for H3N(CH2)nNH3SiF6salts (n = 2, 3, 4, 6). The DSC measurements (heating/cooling) recorded in the 35-245°C temperature domain showed the NH3(CH2)3NH3SiF6 decomposition above 30 °C, which is checked and analyzed by TGA-dTGA techniques. The vibrational spectra interpretation is developed based on theoretical group analyses considering the +NH3(CH2)3NH3+ cations and the SiF62-anions in the C1(4) and Ci(2) symmetry sites, respectively. The SiF62-degenerated modes splitting is explained by the site effect, resulting in symmetry lowering from Oh to Ci in the crystal. The Infrared spectrum analysis at lower N-H and C-H frequencies region showed the presence of medium to strong N-HF hydrogen bonding in the title compound.

STRUCTURAL, MORPHOLOGICAL AND VIBRATIONAL STUDIES OF MAGNESIUM DOPED LITHIUM TITANATE ANODE MATERIALS FOR LI-ION BATTERIES

In the present paper, we study the results of the substitution of Mg2+ in Li4Ti5O12 anode materials with the chemical composition of Li4-xMgxTi5O12 with x = 0, 0.1 and 0.3. Spinel structured Li4-xMgxTi5O12 materials are prepared by conventional ceramic method. The structural, morphological, chemical compostion and vibrational studies of the prepared anode samples are systematically characterized by thermal analysis, XRD, SEM, EDS and FT-IR. Phase formation is confirmed by thermal analysis followed by the XRD and FT-IR spectroscopic results. The X-ray diffraction (XRD) technique exposed that the materials belonged to spinel type having the space group as Fd-3m. Synthesized samples are quite large upto 0.98 to 1.3 ?m in diameter and the grain size had a wide distribution range. EDS is used to identify the elements. The FT-IR spectra show tetrahedral and octahedral sites to be inhabited by the MO6 oxide lattice.